<p>Hypo, a computer program that performs case-based reasoning in the legal domain, helps attorneys analyze and make arguments about new fact situations in terms of the most relevant precedent cases. To perform this task, Hypo must make factual comparisons of cases relative to the problem situation and determine the legal significance of comparisons in terms of arguments about the problem situation. The authors describe techniques that Hypo uses to compare cases, choose the best cases for evaluating, and construct arguments about a new fact situation. They demonstrate how Hypo critically compares a problem situation to the most relevantly similar precedent cases to outline an argument regarding how to decide the current fact situation (CFS) based on its significant similarities to and differences from most on point cases (MOPCS). Hypo's main tool for this task is the claim lattice mechanism. The authors present a detailed example of a claim lattice actually generated by Hypo to analyze a real legal case.</p>